Carbon dynamics of regrowth and mature tropical forests derived from a pantropical database

Abstract:

Tropical forests play a critical role in the global carbon (C) cycle in that they store ~45% of terrestrial C and constitute the largest component of the terrestrial land C sink. Despite the central importance of tropical forests to the global C cycle, knowledge of their ecosystem-level C cycles remains limited, hampering scientific and societal efforts to quantify C budgets across the tropics and to model tropical forest- climate interactions. A particularly important knowledge gap is how C stocks and fluxes vary over the course of tropical forest regrowth following stand-clearing disturbances. To advance understanding of pantropical patterns of the C dynamics of forest recovery, we have compiled a new database, the Tropical Forest C database (TropForC-db), which is the largest and most comprehensive database on ground-based measurements of C stocks and flows throughout the tropics and contains data on disturbance history. This database contains 3,478 records from 788 stands in 163 geographically distinct areas, making it the largest and most comprehensive database on ground-based measurements of C stocks and flows in tropical forest ecosystems. Using TropForC-db, we provide descriptive statistics on C stocks and fluxes for tropical forests subsetted by age class and, when possible, by disturbance and climate history. Furthermore, we show that the rate of biomass accumulation in regenerating tropical forests is jointly shaped by climate and disturbance history. Specifically, forest regeneration is fastest in plantations and slowest following cultivation or grazing, and its rate decreases with increasing precipitation seasonality. We expect that TropForC-db will prove useful for model evaluation and for quantifying the contribution of tropical forests to the global C cycle.